“I don’t think it’s written anywhere that every single nominee goes through on a voice vote,” McConnell said. “We’ve opposed some of them, but they’ve still been confirmed.”

Growing Acrimony?

The larger Senate majority of 56 Democrats and two independents against 41 Republicans has eased the legislative debate. Democrats have a large enough majority to reject most Republican amendments, in contrast to the narrower margins in the 110th Congress that fueled more filibusters and blocked amendments.

But after passing legislation such as an economic stimulus (PL 111-5) and a fiscal 2009 omnibus spending bill for government agencies (PL 111-8), the open question is when growing acrimony over nominations will spill into the legislative arena.

“We don’t have a majority. It’s very difficult to pass legislation,” McConnell said. “What we’ve done in the Senate is offer a variety of options on every bill that’s come up, things that we think would improve the legislation and move it in a more centrist direction.”

Despite a lingering Cabinet vacancy for Health and Human Services secretary, Obama has set a brisk pace for confirmations.

By April 21, Obama had formally nominated 163 individuals and won confirmation of 63, compared with 67 and 30 for Bush at the same point in his presidency.

But Obama, who celebrates his 100th day in office April 29, would need 83 confirmations by that date in order to match the number set by President Ronald Reagan with a Republican-controlled Senate in 1981.

“This data represents a substantial pace,” said Terry Sullivan, executive director of the White House Transition Project, a nonpartisan group of scholars, universities and think tanks that studies transitions. “They seem well on their way to a significant amount of nominations for the first hundred days.”

But Norman J. Ornstein, resident scholar of Congress at the conservative American Enterprise Institute, said that even though Obama is outpacing his predecessor, he would like to move even faster. Republicans, on the other hand, can amplify their positions by challenging the administration.

“If you stand up for your favorite constituents, they’re going to be happier,” Ornstein said. “You may be able to bludgeon people or pressure the administration through delays or holds to temper a policy or make a promise about something you will do or won’t do.”

Nominees Under Scrutiny

Disputes are growing more pronounced:

• Christopher Hill was confirmed as ambassador to Iraq, 73-23, on April 20. But with opposition led by Republican Sam Brownback of Kansas about Hill’s lack of experience in the Middle East and his diplomatic history with North Korea, the vote came only after a delay that extended through the two-week April recess and a procedural vote to limit debate.

• Judiciary Chairman Patrick J. Leahy , D-Vt., scheduled a hearing April 29 for federal Judge David F. Hamilton’s nomination to the 7th U.S. Circuit Court of Appeals after Republicans boycotted an earlier hearing because they said they hadn’t had enough time to prepare.

Conservatives have criticized Hamilton as a liberal activist, particularly for his injunction against an Indiana law that required women to wait 18 hours after receiving in-person abortion counseling before getting an abortion. Hamilton has the backing of that state’s Republican senator, Richard G. Lugar .

• Republican John Barrasso of Wyoming said he would oppose the nomination of Regina McCarthy to be assistant administrator for air and radiation at the Environmental Protection Agency, in a dispute over a finding of climate endangerment.

The Environment and Public Works Committee approved her nomination April 23, but Chairwoman Barbara Boxer , D-Calif., said a cloture vote might be needed on the floor to confirm McCarthy.

• Dawn Johnsen, an Indiana University law professor nominated to head the Justice Department’s Office of Legal Counsel (OLC), faces a potential filibuster from Arlen Specter of Pennsylvania, the ranking Republican on the Judiciary Committee.

Johnson has been criticized for her previous work as head of legal policy for NARAL Pro-Choice America and for criticizing the OLC’s counterterrorism policies during the Bush administration.

“She may be good somewhere else, but she’s not good there,” said Orrin G. Hatch , R-Utah.

Republican Jeff Sessions of Alabama said that, as a former Justice Department lawyer, he’s concerned about Obama packing the agency with liberals. He opposed Hill and questions the nominations of Hamilton and Johnsen.

“There is a growing frustration in the Judiciary Committee about a pattern of far-left nominees,” Sessions said. “I believe the president deserves deference, but he’s about used all the deference he’s going to get out of me.”

Leahy said he wasn’t sure what Republicans were accomplishing by opposing Justice Department nominees.

“They’re not helping themselves with the American public,” Leahy said. “Especially at a time when people are concerned about law enforcement, concerned about crime, and these guys are holding up the nominations that involve fighting crime.”

But Republicans said the disputes are part of the routine course of reviewing nominations.

Noted South Carolina’s Lindsey Graham , “People have had up-and-down votes and that’s the goal, right?”